Filter unit for intake air of helicopter turbine engines



FIG. 1 is a perspective view from top, front and left side showing my new design for a filter unit for intake air of helicopter turbine engines;

FIG. 2 is a side elevational view from the left side thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a side elevational view from the right side thereof;

FIG. 5 is a bottom plan view thereof; and,

FIG. 6 is a top plan view thereof.

The back view thereof is devoid of ornamentation and forms no part of my inventive design. 

The ornamental design for a filter unit for intake air of helicopter turbine engines, as shown and described. 